We have developed a stereo vision system for observing real objects for experimental physics demonstration. The stereo vision observes objects from two different points of view. An observer can identify the distance and velocity of an object based on at least two different points of view. This paper demonstrates our comprehensive observation in a pendulum oscillation experiment to test the stereo vision system where a stereo camera is in a forward view position. The stereo camera produces stereo images. We use automatic object tracking techniques to obtain the 3D position of the pendulum in real space based on the sequential stereo images of the pendulum movement. The experimental results in a 3D graph that shows the trajectory of the pendulum oscillation. We confirm the common understanding of the oscillation movement by obtaining the graph of the pendulum oscillation as a function of time. We can obtain the oscillation motion parameters such as amplitude, angular frequency, frequency, period, and initial phase. Also, we can show the damping oscillation phenomena and the damping factor.